| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a semiconductor integrated device, capable of easily measuring frequency of a PLL circuit incorporated in a semiconductor integrated circuit and inspecting locking/re-locking, only with a digital circuit, without increasing an analogue circuit for inspection. <P>SOLUTION: The semiconductor integrated device comprises a VCO4, a frequency-dividing circuit 5 that divides the output of the VCO4, a phase comparison circuit 6 that subjects the output of the frequency-dividing circuit 5 to phase comparison with a clock CLK1, a charge pump control circuit 9 for controlling a charge pump by external digital signals RST and SET, a charge pump circuit 7 for charge pumping, according to phase difference signal from the phase comparison circuit 6, an LPF8 that supplies only the low-band components of the output of the charge pump circuit 7 to the VCO4, and a PLL frequency measuring circuit 10 that measures the frequency of the output signal VCO4. The control signal for the charge pump circuit 7 is constituted to be set from the external digital signals SET and RST. <P>COPYRIGHT: (C)2004,JPO&NCIPI |
